Bubble cap



Nov. 10, 1936.

BUBBLE CAP Original Filed Feb. 19, 1934 w a Q FIGURE 2.

I THEODORE-O.WENTWORTH,

I ATTORNEY T. o. WENTWORTH 2,060,601

Patented Nov. 10, 1936 PATENT OFFICE BUBBLE car Theodore 0. Wentworth,Cincinnati, Ohio Reflled for abandoned This invention relates toimprovements in bubble caps for effecting contact and heat transferbetween vapors and liquids. In the art of distillation andrectification, it is particularly important to secure a means-andapparatus for intimately mixing or contacting vapors of the liquid orliquids being distilled with a wash liquid. This usual equipment takesthe form of a rectifying column; and it is with the bubbling caps usedin such a column for such contacting of liquid and vapor that my presentinvention deals.

One object of my invention is the securing of va means for the efficientmixing of a vapor or gas with a liquid on'the trays or plates of adistilling column. A second object is the reduction of the total numberof trays or plates required for said distilling column in the separationof volatile liquids by rectification. Still another object is the mixingof vapors with a liquid by the action of suitably directed streams ofsaid vapors impinging on each other in the body of said liquid. Stillother objects and effects will hereinafter appear.

The invention will be described with reference to the accompanyingdrawing, in which:-

- Fig. 1 is a diagrammatic vertical sectional view of a preferred formof my bubble cap showing one method of attaching it to the plate.

- Fig. 2 is a horizontal cross-section on the line A-.A, Fig. 1, showingthe two shapes of teeth utilized to secure the desired effects.

Fig. 3 is an enlarged cross section oi a small sector for the capillustrating the action of the vapors in the liquid.

Fig. 4 illustrates a. diagrammatic cross-section of a section of arectifying column showing the relation of the caps to the structure of arectifying column as a whole.

In the drawing, like parts are referred to by like symbols, and in Fig.1, I is a section of the plate or tray of a distilling column, and 2 is.the thimble having a general cylindrical shape of smaller diameter thanthe hole in the plate, and

being formed with. a flange 3 to fit againstv the lower surface of theplate. Passageways 411:, one

at each side of the spider-arch 4, allow vapors 1 to pass through thetop or the thimble while the arch supports a threaded stem 5 whichpasses through the hole in the top of the cap 3. Look nuts I threaded onthe stem are employed to secure the cap to the thimble and thus to theplate.

The teeth 8 and 8 of special shape have slots between them through whichvapors issue.

In Fig. 2, the combination of teeth 8 of a general triangular shape, andteeth 8 of a general February 19, 1934. November 8, 1935, Serial No.

application Serial No. This application 48,863

semicircular shape are illustrated to provide slots l0 between them forthe passage of vapors.

Fig. 3 shows that the jets of vapor la and Nb issuing through the slotsI0 assume the form of streams having a general direction roughly tan- 5gential to the periphery of the cap itself. Since these streams areopposed in direction, they meet at a vertical line of the same height asthe depth of the slots.

Fig. 4 illustrates the general arrangement of a plurality of such caps 6on plates l of a rectifying column in conjunction with a shell 20, andvertical flow pipes or -downcomers" 30 for the passage of a wash liquidfrom higher to lower plates.

The art of rectification depends on contacting vapors with liquids andis usually practiced in vertical columns of one of three general types;(a) .packed{ (b) curtain; (c) bubble cap, The contacting action in (a)is due to the trickling 20 of liquid in thin streams down the surfacesof filling bodies, around and through'whlch vapor streams rise.

In the curtain type column, exemplified by patent to Schneible, No.1,794,986, and German patent to Komorek, No. 497,905, the streams ofliquid are allowed to fall in thin films orcurtains from plate to plate;and the vapors are passed at right angles through these curtains intheir travel to the top of the column.

For various reasons, the column most often used is the bubble cap typein which bubbles of vapor are compelled to travel through layers of.liquid spaced above each other. The energy required for the agitation ofvapor and liquid on each plate or tray is supplied by the successiveexpansion of the vapors from a pressure accumulated in the still pot tothe lower pressure existing in the condenser. While advantage has beentaken of this pressure to secure intimate mixing in various types ofbubble caps, such as the ejector nozzle of U. S. Patent No. 1,741,519,and the air lift" principle of U. S. Patent No. 1,821,619, as well asthe more common slotted or serrated edge, vertically or horizontallyplaced, in common use, I have found that the opposed tangential jetaction which I employ gives a more efficient mixing with a more simplyconstructed cap than any of these.

Moreover, a principal cause for the very high efficiency of my bubblecap resides in the fact that the two streams of vapor, by impinging atan angle a short distance from the periphery of the cap, violently mixthe entrained liquid and other surrounding liquid to form the vortex ofa miniature waterspout' which contacts the liquid and the vapor soemciently that the particles of each are very minute, and a substantialequilibrium is more nearly approached.

This action has been carefully observed, and the unusual shape of theteeth precisely determined i'or maximum efiiciency by enclosing platesof a distilling column within a glass shell such as 20 and examining theaction produced on the plates by caps in which the slots were slightlydifferent in size and arrangement.

I have found that the use of my bubble cap gives a comparable increaseof efflciency in those operations related to rectification such as, forexample, the washing or scrubbing of gases by a liquid flowing incounter-current to the gas stream, or the accomplishing of a chemicalreaction in the liquid or gaseous phase, when the reaction is aided bythe presence of two such phases.

My bubble cap has the additional advantage that it may be readilymanufactured in large quantities of any material which may be resistantto corrosion in the particular liquids and vapors encountered. It may bereadily produced by casting in one piece as shown and it requires nomachining, punching, or drilling as is common in the quantity productionof older forms of bubble This application is a substitute for abandonedapplication No. 711,892, filed February 19, 1934.

-Having described my invention, what I claim and desire to secure byLetters Patent, is as follows:

1. In apparatus of the character described, a bubble cap internallyformed to receive vapor and provided with a plurality of peripheralteeth, successive teeth in cross-section being substantially triangularand substantially semi-annular.

2. In apparatus of the character described, a bubble cap internallyformed to receive vapor and provided with peripheral teeth, alternateteeth being substantially triangular with the apex of the triangledirected toward the axis of the cap and intermediate teeth each havingsurface areas contiguous to walls of two of said triangular teeth and inconformity therewith whereby the opposed separated walls of the two setsof teeth form angular vapor stream guides.

THEODORE O. WENTWORTH.

